While it's not unusual to see carbon fiber patterns on cases for Apple products, the real thing is more of a rarity -- a thin, light, ultra-tough, and expensive material. As such, using real carbon fiber can make the cost of accessories prohibitively high. Element Case has decided to incorporate it into two of its new designs, Formula ($60) and Ion ($50), though rather than making them entirely out of carbon fiber, the company used backplates that create the same effect without making the cases too expensive.

Formula is like many other hard plastic slider-style cases, but instead of straight edges, the corners bulge and create a shape slightly resembling a bone. It slides apart at the bottom along a break that juts up on the right side. The top half of the slider is almost completely covered by the carbon fiber plate, which runs from the bottom past the teardrop-shaped camera hole.

The case offers very little protection for the inputs and outputs of the device. Along the bottom, a long opening runs from the microphone on the left to speaker on the right; even oversized cords will fit without issue into the Dock Connector port, but docking with most devices will require removing the bottom cap. On the upper left edge is another combined opening. This one is for the side switch and volume buttons, and is large enough to accommodate both GSM and CDMA iPhone 4s. The headphone port and noise-canceling mic are exposed on the top, but the Sleep/Wake button is protected. We really like the tactility of the hard plastic button cover, and would like to have seen this material used for the volume buttons as well. A neat touch on the remaining side is a rubber bumper that feels nice when the phone is held in either hand. Unfortunately, the glass display is completely unprotected as the case’s edge sits flush against it, and no screen film is included in the package.

Ion has the same general shape as Formula, but instead of a slider, it is a shell-style case with much better front coverage. The body is mostly semi-firm rubber, save for the carbon fiber back plate that covers most of the back; only the top left and bottom right corners are not covered. The rubber wraps around to cover some of the bezel, with even more protection at the bottom near the Home button. We really appreciate this coverage, especially by comparison with what Formula has to offer. One downside to Ion is that it lacks Sleep/Wake button coverage.

Both Formula and Ion have individual features that would make the other more complete: Ion’s front coverage and Formula’s button protection would certainly have created a best-of-all-worlds alternative if they were available on the same case. As they are, however, each case is pretty good, more noteworthy for the inclusion of carbon fiber than anything else. Of the two, we would recommend Ion more readily, as it is less expensive and we consider its passive screen protection—the lip around the screen—to be more of an asset than Formula’s button covers; Ion deserves a B rating. For $10 more, we offer a limited recommendation of Formula. We still really like the look and feel, but it’s simply not as protective.

Editors' Note: iLounge only reviews products in "final" form, but many companies now change their offerings - sometimes several times - after our reviews have been published.
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